Vacuum excavator tank and door system

ABSTRACT

A collection tank for a mobile vacuum excavator includes a front with a closed end, a rear with an open end, a door configured to be closed over the open end, and a linkage assembly having a first end attached to the door and a second end attached to the body. A first pivotal movement drives the first end and second end away from each other, and a second pivotal movement moves the first end and the second end toward each other. An actuator is attached to the first arm and to the second arm so that actuation of the actuator in a first direction drives the first pivotal movement and actuation of the actuator in a second direction drives the second arm the second pivotal movement.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 63/040,394 filed Jun. 17, 2020, the entire content ofwhich is hereby incorporated by reference herein.

FIELD OF THE INVENTION

The present disclosure relates generally to a vacuum excavator systemfor removing soil to expose underground utilities (such as electricaland cable services, water and sewage services, etc.), and moreparticularly to an improved vacuum tank and door system for use withsuch system.

BACKGROUND OF THE INVENTION

With the increased use of underground utilities, it has become moreimportant to locate and verify the placement of buried utilities beforeinstallation of additional underground utilities or before otherexcavation or digging work is performed. Conventional digging andexcavation methods such as shovels, post hole diggers, poweredexcavators, and backhoes may be limited in their use in locating buriedutilities as they may tend to cut, break, or otherwise damage the linesduring use.

Devices have been previously developed to create holes in the ground tonon-destructively expose underground utilities to view. One design useshigh pressure air delivered through a tool to loosen soil and a vacuumsystem to vacuum away dirt after it is loosened to form a hole. Anothersystem uses high pressure water delivered by a tool to soften the soiland create a soil/water slurry mixture. The tool is connected with avacuum system for vacuuming the slurry away into a collection tank. Thetank may then be emptied by opening a door on the tank.

Certain prior art vacuum systems are provided with a tank having amanually closing door that is locked in a closed position by latches,locks or other suitable locking mechanisms. Another example of a priordoor system is presented in U.S. Pat. No. 7,837,050, the entiredisclosure of which is incorporated herein for all purposes.

SUMMARY OF THE INVENTION

An embodiment of the present disclosure provides a collection tank for amobile vacuum excavator, including a generally cylindrical body having afront with a closed end, a rear with an open end having a periphery, adoor having a periphery that abuts the periphery of the open end whenthe door is closed over the open end, and a linkage assembly having afirst end attached to the door so that the first end moves with movementof the door and a second end attached to the body of the collectiontank. The linkage assembly includes a first arm, a second arm pivotallyattached to the first arm so that a first pivotal movement of the firstarm and the second arm with respect to each other drives the first endand the second end away from each other and so that a second pivotalmovement of the first arm and the second arm with respect to each othermoves the first end and the second end toward each other. An actuator isattached to the first arm and to the second arm so that the actuatormoves with movement of the first arm and with movement of the second armand so that actuation of the actuator in a first direction moves thefirst arm and the second arm in the first pivotal movement and so thatactuation of the actuator in a second direction moves the first arm andthe second arm in the second pivotal movement.

In another embodiment, a collection tank for a mobile vacuum excavatorincludes a generally cylindrical body including a front with a closedend, a rear with an open end having a periphery, a door having aperiphery that abuts the periphery of the open end when the door isclosed over the open end, and a linkage assembly having a first armpivotally attached to the body at a mounting end about a mount axis, asecond arm pivotally attached to the door at a mounting end about a doorclosure axis, so that the mounting end moves with movement of the door,and pivotally attached to the first arm at a door latch axis. A firstpivotal movement of the first arm and the second arm with respect toeach other drives the mounting end of the first arm and the mounting endof the second arm away from each other and a second pivotal movement ofthe first arm and the second arm with respect to each other drives themounting end of the first arm and the mounting end of the second endtoward each other, wherein the second arm has a distal end and wherein adoor latch plane is defined by the mount axis and the door closure axis.A powered cylinder actuator is attached to the first arm and to thesecond arm so that the actuator moves with movement of the first arm andwith movement of the second arm and so that retraction of the actuatormoves the first arm and the second arm in the first pivotal movement andso that extension of the actuator in a second direction moves the firstarm and the second arm in the second pivotal movement, wherein the doorlatch axis is on one side of the door latch plane when the actuator isin a retracted state and the door latch axis is on an opposite side ofthe door latch plane when the actuator is in an extended state.

In a further embodiment, a collection tank for a mobile vacuum excavatorhas a generally cylindrical body having a front with a closed end, and arear with an open end having a periphery. A door has a periphery thatabuts the periphery of the open end when the door is closed over theopen end. A linkage assembly has a first end attached to the door and asecond end attached to the body. The linkage assembly comprises a firstarm, a second arm pivotally attached to the first arm so that a firstpivotal movement of the first arm and the second arm with respect toeach other drives the first end and the second end away from each otherand so that a second pivotal movement of the first arm and the secondarm with respect to each other moves the first end and the second endtoward each other, and a linear actuator attached at a first operativeend of the linear actuator to one of the first arm and the second arm,so that the first operative end of the linear actuator moves withmovement of the one of the first arm and the second arm, and at a secondoperative end of the linear actuator to the body proximate the secondend of the linkage assembly so that actuation of the linear actuator ina first direction moves the first arm and the second arm in the firstpivotal movement and so that actuation of the actuator in a seconddirection moves the first arm and the second arm in the second pivotalmovement.

In a still further embodiment, a collection tank for a mobile vacuumexcavator has a generally cylindrical body having a front with a closedend, and a rear with an open end having a periphery. A door has aperiphery that abuts the periphery of the open end when the door isclosed over the open end. A linkage assembly has a first end attached tothe door so that the first end moves with movement of the door and asecond end attached to the body. The linkage assembly has a first arm, asecond arm pivotally attached to the first arm so that a first pivotalmovement of the first arm and the second arm with respect to each otherdrives the first end and the second end away from each other and so thata second pivotal movement of the first arm and the second arm withrespect to each other moves the first end and the second end toward eachother, and a linear actuator. The linear actuator is attached at a firstoperative end of the linear actuator to one of the first arm and thesecond arm so that the first operative end of the linear actuator ismovable about a first axis during the first pivotal movement and thesecond pivotal movement and at a second operative end of the linearactuator to the body so that the second operative end of the linearactuator is movable about a second axis during the first pivotalmovement and the second pivotal movement, and so that actuation of thelinear actuator in a first direction moves the first arm and the secondarm in the first pivotal movement and so that actuation of the linearactuator in a second direction moves the first arm and the second arm inthe second pivotal movement. The linear actuator is attached to the oneof the first arm and the second arm and to the body so that, when thedoor is closed over the open end, the second axis is between the openend and the first axis.

In yet another aspect, a collection tank for a mobile excavator has agenerally cylindrical body with a tank centerline, a front with a closedend, and a rear with an open end having a sealing flange that defines afirst plane perpendicular to the tank centerline. A door is pivotallyconnected to the generally cylindrical body and has a periphery thatabuts the sealing flange of the open end when the door is closed overthe open end. A first linkage arm has an end pivotally connected to thebody. A second linkage arm has a first end pivotally connected to thedoor and a second end. When the door is closed over the open end, thefirst end of the second linkage arm is rearward of the first plane andthe second end of the second linkage arm is forward of the first plane.An actuator has a first end that is pivotally connected to one of thefirst linkage arm or the second linkage arm at a first pivot point lyingin a third plane that is perpendicular to the tank centerline, and asecond end having a second pivot point located between the first planeand the third plane. The first pivot point and the second pivot pointlie in a plane that is parallel to or generally parallel to the tankcenterline.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling description of the present disclosure, including thebest mode thereof directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures, in which:

FIG. 1 is a perspective view of a vacuum-operated earth excavator systemincluding a collection tank door system in accordance with an embodimentof the present disclosure;

FIG. 2A is a side plan view of the vacuum-operated earth excavatorsystem of FIG. 1 ;

FIG. 2B is a side plan view of the vacuum-operated earth excavatorsystem as in FIG. 2A, with certain components as in FIGS. 1 and 2Aomitted for view of a collection tank;

FIG. 2C is a side plan view of the vacuum-operated earth excavatorsystem as in FIG. 2A, viewed from a side of the system opposite of theview of FIG. 2 a and with certain components as in FIGS. 1 and 2Aomitted for view of a collection tank;

FIG. 3A is a schematic view of the hydraulic, electric, water, andvacuum systems of the vacuum-operated earth excavator system of FIGS. 1and 2 ;

FIG. 3B is a detail view of part of the system as shown in FIG. 3A;

FIG. 4 is a partial perspective view of the collection tank of the earthexcavator shown in FIGS. 1 and 2 , including a collection tank doorsystem in accordance with an embodiment of the present disclosure, withcertain components hidden;

FIGS. 5A and 5B are partial plan side views of the collection tank doorsystem as shown in FIG. 4 , in the closed position;

FIGS. 6A and 6B are a partial perspective and a partial plan side viewof the collection tank door system as shown in FIG. 4 , in a partiallyopen position;

FIG. 7 is a partial plan side view of the collection tank door system asshown in FIG. 4 , in a fully open position;

FIG. 8 is a partial perspective view of the collection tank door systemas shown in FIG. 4 , in a fully open position;

FIGS. 9A and 9B are partial plan side views of an embodiment of acollection tank, including a door system, in accordance with the presentdisclosure for use with an earth excavator system as at FIG. 1 , withcertain components hidden;

FIGS. 10A and 10B are partial plan side views of an embodiment of acollection tank, including a door system, in accordance with the presentdisclosure for use with an earth excavation system as in FIG. 1 , withcertain components hidden;

FIGS. 11A and 11B are partial plan side views of an embodiment of acollection tank, including a door system, in accordance with the presentdisclosure for use with an earth excavation system as in FIG. 1 , withcertain components hidden;

FIGS. 12A, 12B, and 12C are a rear view, a partial cross-sectional view,and a partial cross-sectional view of an embodiment of a collectiontank, including a door system, in accordance with the present disclosurefor use with an earth excavation system as in FIG. 1 , with certaincomponents hidden; and

Each of FIGS. 13A, 13B, 13C, 13D, and 13E is a side schematic view of anembodiment of a door system in accordance with the present disclosurefor use with a collection tank of an earth excavation system as in FIG.1 .

Repeat use of reference characters in the present specification anddrawings is intended to represent same or analogous features or elementsof the disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the disclosure,one or more examples of which are illustrated in the accompanyingdrawings. Each example is provided by way of explanation of thedisclosure, not limitation of the disclosure. In fact, it will beapparent to those skilled in the art that modifications and variationscan be made in the present disclosure without departing from the scopeand spirit thereof. For instance, features illustrated or described aspart of one embodiment may be used on another embodiment to yield astill further embodiment. Thus, it is intended that the presentdisclosure covers such modifications and variations as come within thescope of the appended claims and their equivalents.

It should be understood that terms of orientation, e.g. “forward,”“rearward,” “upper,” “lower,” “horizontal,” “vertical,” and similarterms as used herein are intended to refer to relative orientation ofcomponents of the devices described herein with respect to each otherunder an assumption of a consistent point of reference but do notrequire any specific orientation of the overall system. Thus, forexample, the discussion herein may refer to a “forward” or “front” endof an earth excavation system or a generally cylindrical collection tankused therewith, referring to a direction toward the end of the earthexcavator that has a motorized cab or that is configured in a trailerconfiguration to be attached to a vehicle rear end, or a “rearward” endof the earth excavation system or tank, referring to a direction towardthe system's rear, at which the tank door is disposed and opens andcloses against the open end of the tank. The present discussion may alsorefer to “upper” and/or “lower” surfaces of the earth excavation systemand/or its components, generally with regard to the orientation of thesystem as shown in FIGS. 1 and 2 . Terms such as “horizontal” and“vertical,” for example, refer to orientations under an assumption thatan earth excavation system as in FIGS. 1 and 2 is disposed in itsoperative position, such as shown at those figures, on a level,horizontal surface. Such terms may be used in the present disclosure andclaims and will be understood to refer to a relative orientation but notto an orientation of the earth excavation system or its tank withrespect to an external frame of reference. Further, the term “end”should be understood to encompass a part of something and an inward of aboundary or edge thereof, rather than just the boundary or edge.

Further, either of the terms “or” and “one of _ and _,” as used in thisdisclosure and the appended claims, is intended to mean an inclusive“or” rather than an exclusive “or.” That is, unless specified otherwise,or clear from the context, either of the phrases “X employs A or B” and“X employs one of A and B” is intended to mean any of the naturalinclusive permutations. That is, either phrase is satisfied by any ofthe following instances: X employs A; X employs B; or X employs both Aand B, and this is true of similar phrases, such as “at least one of Aor B” or “at least one of A and B,” that may be utilized in thespecification or claims. In addition, the articles “a” and “an” as usedin this application and the appended claims should generally beconstrued to mean “one or more” unless specified otherwise or clear fromthe context to be directed to a singular form. Throughout thespecification and claims, the following terms take at least the meaningsexplicitly associated herein, unless the context dictates otherwise. Themeanings identified below do not necessarily limit the terms, but merelyprovide illustrative examples for the terms. The meaning of “a,” “an,”and “the” may include plural references, and the meaning of “in” mayinclude “in” and “on.” The phrase “in one embodiment,” as used hereindoes not necessarily refer to the same embodiment, although it may.Also, as used herein, the term “attach” means to fasten, join together.An attachment, therefore, may refer to a direct or an indirectconnection between two or more things, and “attach,” with respect to twoor more components A and B, may refer to fastening/joining A and B toeach other directly, so that they physically touch each other, orindirectly, so that they are joined to each other through one or moreother components.

Referring to FIGS. 1 and 2 (which should be understood to encompassFIGS. 2A, 2B, and 2C), an earth excavator system 10 generally includes awater reservoir tank (in this embodiment, a pair of tanks) 12, acollection tank 14, a motor 16 (which, in the illustrated embodiment maybe the vehicle engine, delivering power through, e.g., a mechanical,hydraulic, or electric transmission system, but which may also be, e.g.,a dedicated motor mounted on the chassis aft of the vehicle cab), and anearth removal system 18, all mounted on a mobile chassis 24 thatsupports the various components. In the present embodiment, excavatorsystem 10 includes chassis 24 of a motor vehicle 20 (which may also beconsidered part of the excavator system). It should be understood thatwhile the hereindescribed components of earth excavator system 10 areillustrated mounted on chassis 24 of a self-propelled motor vehicle 20with a dedicated motor that propels the apparatus, the system may alsobe supported on the chassis of a trailer (not shown) that can be towedor otherwise moved by a motorized vehicle such as a car, truck, or skidsteer and that may therefore include a tongue and/or hitch coupler toconnect to the separate vehicle. It should be understood that thecomponents of the system may be either directly mounted to the chassisor indirectly mounted to the chassis through connections with othersystem components. Apparatus 10 includes a front 11, a rear 13, and alongitudinal axis 129 that extends through front 11 and rear 13.

The connections of the various components of system 10 are illustratedschematically in FIG. 3 . Referring to FIGS. 1, 2, and 3 , the vacuumexcavator system 10 includes a wand 4 (FIG. 3B) for directingpressurized water W toward earthen material to cut the earthen material.Wand 4 is connected to an excavation fluid pump 6 that supplies water towand 4 via a high-pressure water hose 70. Pump 6 may supply a pressureof, for example, at least about 500 psi or at least about 1,000 psi(e.g., from about 1,000 psi to about 5,000 psi or from 1,000 psi toabout 3,000 psi).

In some embodiments, wand 4 includes a rotary nozzle 8 (FIG. 3B) fordirecting water W toward the earthen material to cut the earthenmaterial. Generally, any rotary nozzle that causes the water to bedirected toward the earthen material in a circular path at the site ofthe excavation may be used. Such rotary nozzles may include a rotorinsert with blades that rotate around a longitudinal axis of the nozzlewhen water is forced through the nozzle. The rotor insert may includethree or more channels that force fluid to flow in different pathwaysthrough the rotor insert to cause the water to move along a circularpath as it contacts the excavation material (i.e., the water moveswithin a cone that extends from the nozzle toward the excavatedmaterial). In other embodiments, a straight tip nozzle that directsfluid along a straight path in a concentrated jet may be used.High-pressure water hose 70 is connected, via a valve, to fluid pump 6to provide water to the earth removal system as selected by the user. Asthe system is used to dig a hole, a distal end of wand 4 is presseddownwardly into the ground. For larger diameter holes, wand 4 is movedin a generally circular manner as it is pressed downward, therebyremoving material from a large cross-section area. Slurry formed in thehole is vacuumed through hose 5 and accumulates in collection tank 14.Once the excavation is completed and the utility is exposed, the vacuumsystem can be shut down, and the operators may examine or repair theutility as needed.

Vacuum excavation system 10 includes a vacuum system 7 (FIG. 2A) forremoving spoil material from the excavation site. Spoil material orsimply “spoils” may include, without limitation, rocks, cut earthenmaterial (e.g., small particulate such as sand to larger pieces of earththat are cut loose by the jet of high pressure water), slurry, and waterused for excavation. The spoil material may have a consistency similarto water, a slurry, or even solid earth, organic material, or rocks. Theterms used herein for materials that may be processed by the vacuumexcavation system such as, for example, “spoils,” “spoil material,” “cutearthen material” and “water,” should not be considered in a limitingsense unless stated otherwise.

Vacuum system 7 includes a vacuum pump system 33 and a boom 9 that iscapable of rotating toward the excavation site to remove material fromthe excavation site. Boom 9 may include a flexible portion, such as ahose, 5 (FIGS. 1 and 3A) that extends downward to the ground to vacuumspoil material from the excavation site. Flexible portion 5 may bemanipulated by a user to direct the vacuum suction toward the excavationsite.

Vacuum system 7 acts to entrain the cut earth and the water used toexcavate the site in a stream of air. A blower or vacuum pump 31 (FIG.3A) pulls a vacuum through boom 9 to entrain the material in theairstream. Air is discharged from the blower 31 after material isremoved from the airstream.

The airstream having water and cut earth entrained therein is pulledthrough boom 9 and through a series of conduits and is pulled intocollection tank 14. The collection tank 14 removes at least a portion ofcut earthen material and water from the airstream. Air exits one or morecollection tank air outlets 27 through one or more conduits 25 and isintroduced into cyclones 11 (FIGS. 1 and 3A) via conduit 25 to removeadditional spoil material (e.g., water, small solids such as sand, lowdensity particles such as sticks and grass, and the like) not separatedin the collection tank. Material that collects in the bottom of thecyclones 11 is conveyed by a cyclone discharge pump (e.g., peristalticpump) or, alternatively, is gravity fed to a dewatering system. The airremoved from cyclones 11 is introduced into one or more filter elementsbefore entering vacuum pump 31. Vacuum pump 31 may be disposed in ornear the engine compartment. Air is removed from the apparatus through avacuum exhaust 29.

Vacuum pump 31 generates vacuum in the system to pull water and cutearthen material into system 10 for processing. In some embodiments,vacuum pump 31 is a positive displacement pump. Such positivedisplacement pumps may include dual-lobe or tri-lobe impellers (e.g., ascrew rotor) that draw air into a vacuum side of the pump and forces airout the pressure side. The pump may be powered by a motor having a poweroutput of, for example, at least 75 hp, at least 100 hp or even at least125 hp.

One or more example vacuum excavation systems such as may be utilizedwith or encompassed by the systems and methods disclosed herein aredisclosed in the U.S. patent application Ser. No. 16/630,057, entitled“Hydro Excavation Vacuum Apparatus Having Deceleration Vessels andMethods for Hydro Excavating a Site, filed Jan. 10, 2020, the entiredisclosure of which is incorporated by reference herein for allpurposes.

Referring additionally to FIG. 4 , collection tank 14 has a generallycylindrical body 15 having a closed front end 17 (FIGS. 2B and 2C) andopen rear end 19 (FIG. 8 ). A discharge door 126 is connected to theopen rear end 19 of the tank body 15 by a hinge 128 that allows the door126 to swing open, thereby providing access to the tank's interior forcleaning. A pair of hydraulic cylinders may be provided for tilting theforward end of tank 14 upwards in order to cause the contents to runtowards discharge door 126. A gate valve 140, coupled to a drain 142 indischarge door 126, drains the liquid portion of the slurry in tank 14without requiring the door to be opened. Gate valve 140 may also be usedto introduce air into collection tank 14 to reduce the vacuum in thetank so that the door 126 may be more easily opened.

Optionally running the length of the interior of collection tank 14 is anozzle tube that includes nozzles for directing high pressure waterabout the interior of the tank, and particularly towards the base of thetank. The nozzles are actuated by opening a valve connected to a waterpump (e.g. water pump 6), which delivers high pressure water from thepump to the nozzles for producing a vigorous cleaning action in thetank. When the nozzles are not being used for cleaning, a small amountof water is allowed to continuously drip through the nozzles topressurize them so as to prevent dirt and slurry from entering andclogging the nozzles.

The hydraulic cylinders, used to tilt collection tank 14, may bepowered, e.g., by an electric hydraulic pump (not shown) provided forthe purpose, by the power source (engine) of the truck, or by theindependent power source for the vacuum. The hydraulic pump connects toa hydraulic reservoir and is driven by the electrical system providedfrom the motor. A high-pressure output line and a return line connectthe hydraulic pump to the hydraulic cylinders.

Earth excavator system 10 can be used to dig multiple holes beforehaving to empty collection tank 14. However, once collection tank 14 isfull, it can be emptied at an appropriate dump site. When ready to opendischarge door 126, vacuum pump 31 is shut down, and the vacuum pressureis released so that air enters the tank, thereby allowing the internalpressure of the tank to match the ambient atmospheric pressure andallowing the door to be opened. Once the door is opened, the hydrauliccylinders can be activated to raise forward end 17 (FIG. 2 ) upward,dumping the slurry from the tank. For this purpose, tank 14 is pivotallyattached to chassis 24 (FIGS. 1 and 2 ) at a pair of hinges 90A and 90Bthat include relatively pivotable portions that pivot about an axis 88(FIG. 4 ) transverse to axis 129 to allow tank 14 to pivot about axis 88as the hydraulic cylinders move the tank's forward end up and down, andsuch that when the hydraulic cylinders push the tank's forward endupward, liquid and solid matter retained in collection tank 14 may bedischarged through the tank's open end.

Referring now to FIGS. 4, 5A, and 5B, collection tank 14 is equippedwith a sealing flange 74 that defines a perimeter about the tank body'sopen end 19 (FIG. 8 ), discharge door 126 that is pivotally connected tothe tank body by a pair of slotted hinges 128, and a discharge doorlatching system 80. Hinges 128 are slotted hinges, thereby allowing theportions of the hinges on the door to move slightly back and forth onthe hinge pins in the direction of axis 129 as door 126 pivots to andaway from the tank opening. As door 126 moves upward in the openingdirection, hinges 128 allow the door's slight movement to allow thedoor's edge to clear the tank open edge. As door 126 moves down in theclosing direction, hinges 128 allow the door to move back in the otherdirection so that the door seats evenly against the tank open endperiphery.

Discharge door latching system 80 has two linkage assemblies 100A and100B, each including an upper linkage arm 102, a lower linkage arm 104,and an actuator (in the illustrated embodiment, a linear actuator, e.g.a hydraulic cylinder). For ease of discussion, reference will be madeprimarily to linkage assembly 100A, where all reference numbers areannotated with a capital “A.” However, it should be understood that thesame components exist for linkage assembly 100B, as a mirror image oflinkage assembly 100A.

As should be understood, a linear actuator is an actuator that createsmotion in a straight line, which may be referred to as the actuationdimension. Examples of linear actuators include, but are not limited to,mechanical actuators (such as screws, rack and pinion devices, beltdrives, hydraulic cylinders, and pneumatic actuators),electro-mechanical actuators, and linear motors. Thus, while hydrauliccylinders are used in the examples described herein, it should beunderstood that this is for purposes of example only and that otherlinear and non-linear actuators may be used to drive one or more linkageassemblies as discussed herein.

Referring specifically to FIG. 5A, a lower linkage arm 104A is rigidlyconnected to a linkage assembly pivot bar 110 (FIG. 8 ) at the pivotbar's first end 110A so that the lower linkage arm and the pivot barrotate together. As shown, lower linkage arm 104A is connected to pivotbar 110 at a portion of lower linkage arm 104A that is disposed betweena first end 105A and a second end 107A of the lower linkage arm. Pivotbar 110 extends from its first end 110A, through the outer wall ofcollection tank body 15 (FIGS. 2 and 4 ), and into a pivot bar/supporttube 115 (FIG. 8 ) that passes through an internal chamber 111 (FIG. 8 )of tank 14. The pivot bar is pivotable about an axis 113 orientedgenerally parallel to an inner diameter of internal chamber 111 (FIG. 8) of collection tank 14. The pivot bar extends along its axis 113 (whichis also the pivot bar's elongation dimension) through tank internalchamber 111 and further extends through the opposite side of thecollection tank outer wall and terminates at a second end of the pivotbar 110. In embodiments in which the pivot bar 110 extends through thetank internal chamber 111, without a support tube 115 (which may besealingly attached to through holes through the tank wall to receive thebar), a sealed bearing (not shown) may rotatably engage pivot bar 110 atthe point where the pivot bar 110 passes through the collection tankexternal wall to ensure that tank internal chamber 111 (FIG. 8 ) remainssealed from the outside atmosphere. As shown in FIG. 8 , pivotbar/support tube 115 spans interior 111 of tank 14 and providesstructural support to the walls of the tank 14. In other embodiments,both the pivot bar 110 and the support tube 115 may be provided, thoughnot necessarily one within the other as in the embodiments illustratedherein. The rigid connection of lower linkage arms 104A and 104B (FIG. 8) with the respective first and second ends of pivot bar 110 entrainsboth of the lower linkage arms with pivot bar 110 so that the lowerlinkage arms 104A, 104B rotate in unison with the pivot bar 110. Inanother embodiment, pivot bar 110 may be omitted, though the tubingthrough which it passes may be retained, e.g., for structural support.In such embodiments, each of the two lower linkage arms may be pivotallyattached to the tank wall, e.g. about a pin welded or bolted to the tankwall or received within a receiver manufactured into the tank wall.

First end 105A of first lower linkage arm 104A has an actuating cylindermounting hole (not shown) adjacent its distal end. In one or moreembodiments, actuating cylinder 160A is a hydraulic cylinder having acylinder housing 162A and a piston rod 164A that is slidably received inhousing 162A. Piston rod 164A has a free end 166A that is pivotallyattached to a cylinder mounting hole 152A formed at the distal end of asecond end 103A of first upper linkage arm 102A, e.g. by a pin 168A thatextends through both a hole through free end 166A and coaxial hole 152A.The end of cylinder housing 162A is similarly pivotally attached, e.g.by a pin 169A passing through the actuating cylinder mounting hole (notshown) formed in first end 105A of first lower linkage arm 104A and acoaxial hole through the end of cylinder housing 162A. Pins 168A and169A may pivotally attach piston rod free end 166A and cylinder housing162A to the respective cylinder mounting holes by clevis, eyebolt orother similar pivotal linkages.

Referring specifically to FIG. 4 , upper linkage arm 102A has a forwardportion 121 formed in two opposing halves that form a yoke that receivesa rearward portion 123. The open rearward end of forward portion 121receives the forward end of rearward portion 123, and the two ends arefastened to each other, such as by weldment, so that the two portionsform a continuous upper linkage arm. The yoke-type or yoke-shapedarrangement of forward portion 121 allows the forward end 107A of lowerlinkage arm 104A to be received within/between the two yoke halves and,thereby, allows for pivotal connection between the upper and lowerlinkage arms to be made by a pin 144A that passes through both arms, asexplained below. Similarly, the forward free end 166A (FIG. 5A) ofcylinder piston rod 164A is also received within/between the two halvesof the yoke end of the upper linkage arm so that pin 168A (FIG. 5A)passes through the two yoke halves through corresponding holes 152A andthrough a hole through forward free end 166A (FIG. 5A) of the cylinderpiston rod to pivotally attach the hydraulic cylinder to the upperlinkage arm. By such arrangement, the linear actuator, the lower linkagearm, and the upper linkage arm are stacked sequentially with respect toeach other in the vertical direction. Thus, for example, actuatingcylinder 160A is mounted below upper linkage arm 102A and below lowerlinkage arm 104A, which is in turn mounted below upper linkage arm 102A,such that a vertical plane, indicated at 125 in FIG. 4 , simultaneouslypasses through the linear actuator, the lower linkage arm, and the upperlinkage arm, where plane 125 may be considered to be parallel to thecenter line (or longitudinal axis) 129 of generally cylindrical tankbody 15 or to include the dimension of the force vector applied by door126 to peripheral flange 74 (FIG. 5A) when the door is closed over thetank open end and the locking force is applied thereto, as describedherein. Accordingly, the linear actuator is attached to one of the lowerlinkage arm and the upper linkage arm and to the tank body so that, whenthe door is closed over the tank open end, the lower linkage arm, theupper linkage arm, and the linear actuator are disposed with respect toeach other so that a plane passes through each of the upper linkage arm,the lower linkage arm, and the linear actuator and includes a directionof bias of the door periphery into the periphery of the tank open end.This stacking arrangement minimizes the distance that linkage assembly100A (and, similarly, linkage assembly 100B) extends horizontallyoutward from the tank body 15, thereby allowing a tank diameter thatremains within a predetermined overall system width limit but that islarger than would be the case where the linear actuator, the lowerlinkage arm, and/or the upper linkage arm are not stacked verticallywith respect to each other.

Returning to FIGS. 4, 5A, and 5B, pivot pin 144A pivotally connectsfirst lower linkage arm second end 107A with a portion of upper linkagearm 102A that is disposed between its first end 101A and second end103A, thereby allowing the upper and lower linkage arms to pivot withrespect to each other about an axis 136 that passes through pivot pins144A and 144B as the upper and lower linkage arms move with respect toeach other by force applied by the linear actuator, as discussed herein.Axis 136 is generally perpendicular to longitudinal axis 129 and is theaxis about which upper linkage arms 102A and 102B pivot with respect tolower linkage arms 104A and 104B. First end 101A of upper linkage arm102A is configured to adjustably receive a threaded portion of an eyebolt 134A. Eye bolt 134A has an eye (not shown) that is pivotallyconnected to door 126, and more specifically to a first end 146A of across bar 148 that is rigidly secured to a domed panel of discharge door126 so that the upper linkage arm is pivotable with respect to door 126about an axis 132 that passes through the eyes of both eye bolts 134Aand 134B. Axis 132 is generally perpendicular to longitudinal axis 129and is the axis about which door 126 (including cross bar 148) pivotswith respect to the first ends of the first and second upper linkagearms. Moreover, the threaded connection between upper linkage arm firstend 101A and cross bar first end 146A allows for adjustment of the spacebetween the upper linkage arm first end and the cross bar first end inthe direction of the bias force vector applied by the door into thetank's open end periphery 74 (FIG. 8 ).

FIGS. 7 and 8 illustrate collection tank 14 with discharge door 126 in afully open position, in which piston rod 164A of actuating cylinder 160A(and the piston rod of the opposing linear actuator 160B) is in theretracted position. Linkage assemblies 100A and 100B and pivot bar 110cooperate with hinges 128 to rotate discharge door 126 between thisfully opened position and the sealing engagement with collection tankflange 74 in the door's fully closed position. When closing thedischarge door from its fully open position, actuating cylinder 160Abegins to extend piston rod 164A. The pivotal pin connection 168Abetween piston rod free end 166A (FIG. 5A) and second end 103A of upperlinkage arm 102A forces upper linkage arm 102A to pivot in the clockwise(CW) direction 154 about pivot point 144A where upper linkage arm 102Ais pivotably connected to lower linkage arm 104A. Simultaneously, lowerlinkage arm 104A begins to pivot in the counter-clockwise (CCW)direction 156 about axis 113 of pivot bar 110. Continued extension ofpiston rod 164A by actuating cylinder 160A causes discharge door 126 tobe similarly rotated in the CW direction 154 about hinges 128, as shownin FIG. 6B.

With reference also to FIG. 2C, actuating cylinder 160B of secondlinkage assembly 100B simultaneously extends piston rod 164B asactuating cylinder 160A extends piston rod 164A, resulting in closingforce being applied simultaneously both to lower linkage arms 104A and104B by their respective cylinders and, thereby, to pivot bar 110. Incertain embodiments, and depending upon the strength of the actuatingcylinders and the linkage arms, actuating cylinders 160A and 160B mayrepresent a system redundancy wherein the actuation of either actuationcylinder is sufficient to force both lower linkage arms to rotate due totheir rigid attachment to pivot bar 110, when provided. In suchembodiments, when pivot bar 110 is used, one of the actuating cylindersmay be omitted without altering the function of the discharge door. Forexample, in an embodiment including only one actuating cylinder, such asfirst actuating cylinder 160A, a rigid connection between the secondlower linkage arm first end 105B and pivot bar second end 110B forcessecond lower linkage arm 104B to simultaneously rotate in response tothe extension of actuating cylinder 160A. Moreover, in such embodimentswhere two actuating cylinders are provided, should one of the actuatingcylinders fail during operation, the other can operate the opening andclosing of the door so as to maintain the system's functional integrity.It should be understood that the lower linkage arms do not necessarilyneed to be rigidly attached to pivot bar 110 but, instead, may beindependently (with respect to each other) rotatably attached to thetank body, obviating the need for the pivot bar. Thus, in thisconfiguration, each actuating cylinder would drive its respective lowerlinkage arm independently of the other actuating cylinder. In certainembodiments, the actuation cylinders may not be sufficiently strong forone of the cylinders to independently drive both linkage assembliessimultaneously. In such and other embodiments, the pivot bar may serveto synchronize the motions of the two linkage assemblies.

In operation, and referring again to FIGS. 2C, 7, and 8 , as lowerlinkage arms 104A and 104B rotate in response to the extension of thecylinder piston rods as described herein, first and second lower linkagearm second ends 107A and 107B rotate in direction 156, allowing upperlinkage arm first ends 101A and 101B to move downward with door 126 asfirst and second upper linkage arms 102A and 102B pivot about pins 144Aand 144B, respectively. Upper linkage arms first ends 101A and 101B movedownward and toward the collection tank open end, controlling the speedat which discharge door 126 rotates downward about hinges 128 in thedirection of arrow 154 by way of the rigid connection between cross bar148 and the domed portion of discharge door 126. Rotation of dischargedoor 126 about door hinges 128 causes discharge door 126 to rotate intoclosing engagement with collection tank sealing flange 74.

As best seen in FIG. 6B, extension of piston rods 164A and 164B alsocauses first and second lower linkage arms 104A and 104B to rotate aboutaxis 113 of pivot bar 110 in CCW direction 156 as first and second upperlinkage arms 102A and 102B (FIG. 8 ) rotate about pivot points 144A and144B. FIGS. 6A and 6B show discharge door 126 in a position between thefully open and fully closed position as piston rods 164A and 164B areonly partially extended. Discharge door 126 has a flange 127 about itsouter periphery that forms a sealed engagement with collection tankflange 74 once the discharge door is fully closed. It should beunderstood that a gasket (not shown) may be attached to one of tankflange 74 or door flange 127 to assist in forming an airtight seal whenthe door in the closed position.

Referring to FIGS. 2C, 4, 5A, and 5B, once discharge door flange 127seats with tank flange 74, actuating cylinders 160A and 160B continue toextend piston rods 164A and 164B. As the piston rods are furtherextended, so that the two linkage assemblies move over center, asdiscussed below, the bottom surface of upper linkage arm 102A makescontact with a portion of the upper surface of lower linkage arm 104A(at 108A—FIG. 5B) forming a rotational stop. The mirror image structureexists within linkage assembly 100B on the opposite side of tank 14. Inanother embodiment, in which rotational stop 108A is not provided viacontact between the upper and lower linkage arms, the rotational stopmay comprise a seating bracket (not shown) attached to the side wall oftank body 15 that receives linkage assembly 100A. A similar seatingbracket on the opposing side of tank body 15 similarly receives linkageassembly 100B. When linkage assemblies 100A and 100B have rotatedsufficiently to make contact with the rotational stops 108A and 108B,and the linkage assemblies are each in an over center locked conditionas described herein, the contact between a portion of the linkageassembly and the rotational stop prevents further rotation.

A discharge door locking feature of latching system 80 is now discussed.For purposes of discussion, axis 136 of pivot points 144A and 144Bbetween the upper linkage arm and the lower linkage arm is referred toas the “door latch axis;” axis 132 between the upper linkage arm and thedoor is referred to as the “door closure axis;” axis 113 of pivot bar110, i.e. the axis of rotation between the lower linkage arm and thetank body, is referred to as the “mount axis;” and mount axis 113 andits parallel door closure axis 132 define a door latch plane 180 (FIG.5B). As best seen in FIG. 5B, rotational stop 108A (and a correspondingrotational stop 108B, not shown, defined in the linkage assembly on thetank's opposite side in mirror image) is positioned such that the bottomsurface of upper linkage arm 102A contacts the upper surface of lowerlinkage arm 104A only when door latch axis 136 crosses from a positionabove door latch plane 180 to a position below door latch plane 180.This condition may be referred to as “rotation beyond over center,” andFIG. 5B shows linkage assembly 100A when placed in this position.Because of the simultaneous movement of both linkage assembly 100A andlinkage assembly 100B, both linkage assemblies respond identically asthey rotate over center.

When door latch axis 136 lies in door latch plane 180 (plane 180 movesfrom its horizontal position shown in FIG. 5B as the multi-arm linkageassemblies move), upper linkage arm 102A is in tension, and lowerlinkage arm 104A is in compression, and the forces can be reduced bymoving door latch axis 136 out of door latch plane 180 in either theopening direction above door latch plane 180 or in the closing directionbelow door latch plane 180. By forcing door latch axis 136 (and pivotpoints 144A and 144B) over center from above to below door latch plane180 (e.g. to the point at which stop 108A precludes further movement),discharge door 126 is biased into the closed position and will remain inthe closed position unless lower linkage arms 104A and 104B are activelymoved back, against the opposing over-center force, across the positionin door latch plane 180 to a position above door latch plane 180. Inembodiments without stops 108A/B, the actuator may prevent furtherrotational movement.

Note, when the discharge door contacts the open end of the tank duringthe closure of discharge door 126, the force exerted by actuatingcylinder 160A on the door is in a direction away from the door. That is,in moving the door into closing contact with the tank's open end, theforce exerted by actuating cylinder 160A (and, correspondingly, by theactuating cylinder on the tank body's opposing side) on the door throughthe linkage assemblies is in a direction that biases the discharge doortoward the tank body's open end. When the door is in the closedposition, the force is parallel to axis 129 (FIG. 4 ).

As apparent in the embodiment illustrated at FIG. 5B, if door latch axis136 is above (in the perspective of FIG. 5B) door latch plane 180, thenwhen upper linkage arm 102A and lower linkage arm 104A (and,correspondingly, upper linkage arm 102B and lower linkage arm 104B) movepivotally with respect to each other so that door latch axis 136 movesin direction 156 (FIGS. 6B and 7 ) and door 127 moves in the closingdirection indicated at 154 in FIG. 7 , first end 101A of upper linkagearm 102A and first end 105A of lower linkage arm 104A (and,correspondingly first end 101B of upper linkage arm 102B and first end105B of lower linkage arm 104B) move toward each other. Again if doorlatch axis 136 is above door latch plane 180, then when upper linkagearm 102A and lower linkage arm 104A (and, correspondingly, upper linkagearm 102B and lower linkage arm 104B) move pivotally with respect to eachother so that door latch axis 136 moves in the rotational directionopposite to direction 156 (FIGS. 6B and 7 ) and door 127 moves in theopening direction opposite to the direction indicated at 154 in FIG. 7 ,first end 101A of upper linkage arm 102A and first end 105A of lowerlinkage arm 104A (and, correspondingly first end 101B of upper linkagearm 102B and first end 105B of lower linkage arm 104B) move away fromeach other. After door latch axis 136 passes over center from above tobelow door latch plane 180, first end 101A of upper linkage arms 102Aand first end 105A of lower linkage arm 104A (and, correspondingly,first end 101B of upper linkage arm 102B and first end 105B of lowerlinkage arm 104B) move slightly apart until stops 108A/B prevent furtherrotational movement. As will be understood in view of the presentdisclosure, this slight movement does not disengage door 126 from itsengagement with the tank open end perimeter. Similarly, when axis 136moves in the opposite, opening, CW direction from such position andtoward plane 180, first ends 101A/B and 105A/B move slightly toward eachother until axis 136 crosses from below to above plane 180, from whichpoint they move away from each other as the door opens.

Actuating cylinders 160A and 160B each includes internal valving, asshould be understood, to prevent loss of hydraulic pressure within thecylinder in the event of a pressure bleed off of the hydraulic supply,meaning that the hydraulic lines to the cylinder lose pressure. As such,actuating cylinders remain in the position in which they exist if thehydraulic system experiences pressure loss.

When opening discharge door 126 from the closed position, actuatingcylinder 160A retracts piston rod 164A inwardly, causing pivot points144A, 144B and axis 136 to rotate about axis 113 in a direction oppositeto arrow 156 (FIG. 7 ) to a position above door latch plane 180. Thisrotation causes upper actuating arm 102A to pivot in the CCW directionabout axis 136 of pivot points 144A and 144B, thereby causing dischargedoor 126 (and axis 132) to pivot upward about a horizontal axis passingthrough hinges 128. Simultaneously, lower actuating arm 102A begins torotate in the CW direction about mount axis 113. As previously noted,actuating cylinder 160B may simultaneously retract piston rod 164B asactuating cylinder 160A retracts its piston rod 164A, resulting in asimilar opening force applied to upper linkage arms 102A and 102B. Thus,as the lower linkage arms rotate in the opening direction, the upperlinkage arms urge the door (e.g. at cross bar 148) to travel oppositethe direction indicated by arrow 154 (FIG. 6B). If provided, pivot bar110 (FIG. 8 ) also rotates, synchronizing the movements of linkageassemblies 100A and 100B.

As actuating cylinder 160A is disposed between upper and lower linkagearms 102A and 104A (and as the cylinder on the opposing side of the tankbody is similarly attached), and travels with them, a shorter cylinderstroke is needed in the illustrated embodiment than would be required ifthe cylinder were attached directly to the side of tank body 15.Additionally, attaching both operative ends of the cylinder directly tothe linkage arms avoids the need to include components for directlyattaching the cylinder to the tank body. Moreover, in embodiments inwhich one end of the actuating cylinder is attached directly to the tankbody, but proximate the attachment to the lower linkage arm, arelatively short stroke may still be obtained.

It should be understood that while, in certain embodiments, thehydraulic cylinder is attached to and between one of the upper linkagearm and the lower linkage arm, and the linkage arms are attached to thedoor and the tank, so that the hydraulic cylinders move the door in theopening direction when the cylinders themselves move in a retractingdirection and move the door in the closing direction when the cylindersthemselves move in an extending direction, this is for purposes ofexample only and not limitation of the present disclosure. In otherembodiments, the linkage arms may be arranged between the door and thetank body, and the hydraulic cylinders (or other linear actuators) maybe arranged between the tank body and the multi-arm linkage assemblies(or within the multi-arm linkage assemblies) so that actuation of thecylinders in the extending direction moves the door in the openingdirection and actuation of the cylinders in the retracting directionmoves the door in the closing direction. Similarly, while one or moreembodiments illustrated or discussed herein provide a linear actuatorattached between the tank body and the upper linkage arm to drive thedoor between the extremes of its movement range, it should be understoodfrom the present disclosure that the linear actuators may be attachedbetween the tank wall and the lower linkage arm for the same purpose.Thus, again, the particular one or more embodiments disclosed herein arefor purposes of example and should not be considered to limit thepresent disclosure.

In one or more embodiments, when discharge door 126 is in the closedposition, the linear actuator is oriented so that its direction ofoperation is generally aligned with the closing or sealing force of thedoor into the peripheral edge flange 74 (FIG. 8 ), generally parallelwith the tank body's cylindrical axis 129 (FIG. 4 ). For example,referring to FIG. 5A, a plane 175 that includes the pivot axis throughpin 168A (and corresponding pin in the linkage assembly on the opposingside of the tank body) about which upper linkage arm 102A pivots withregard to piston rod free end 166A and that includes the pivot axisthrough pin 169A (and corresponding pin in the linkage assembly on theopposing side of the tank body) about which the opposing end of thelinear actuator is pivotally attached to the lower linkage arm includesthe door's bias or force direction (horizontal, in the view of FIG. 5A)and is parallel to tank axis 129 (FIG. 4 ). This arrangement is achievedthrough the positioning of the axis of pin 169A vertically below axis113 by the flange of the lower linkage arm extending between thosepositions. As shown in FIG. 5A, there is a (slightly smaller) verticaloffset between axis 136 and the axis of pivot pin 168A. Thus, the lowerlinkage arm flange extending below axis 113 locates the axis of pin 169Aso that it aligns horizontally with the axis of pin 168A, therebyhorizontally aligning the cylinder's operational dimension. In otherembodiments, a plane passing through the two pivot axes of the linearactuator may be generally parallel (e.g., plus or minus 10 degrees fromparallel) to the tank axis 129 (FIGS. 9B, 10B, 11B, 12B, 13A).

As previously stated, the above discussion is directed primarily tolinkage assembly 100A. However, one of skill in the art shouldunderstand, in view of the discussion herein, that the discussion alsoreflects the construction and operation of linkage assembly 100B (FIG. 4), in mirror image. Moreover, while not shown in the figures, one ofskill in the art should understand that linkage assemblies 100A and 100Bmay be operated by a control panel at the back of the vehicle, at acontrol panel located inside the vehicle, or remotely by a wireless orwired control panel. One or more of these control panels may be providedto operate the automated assembly, among other operations and mechanismsof the machine.

As noted above, the embodiments described above with respect to FIGS.4-8 attach the linear actuator to and between the two arms of each ofthe two dual arm linkage assemblies so that the linear actuator moveswith movement of both arms of the linkage assembly. In sucharrangements, and others discussed herein, the actuator has a relativelyshort stroke in driving the tank door between the extremes of its rangeof travel with respect to the tank open end. The linear actuator'sdisposition in these embodiments, and others disclosed herein, alsolocate the linear actuator sufficiently closely with the multi-armlinkage assembly that space below the multi-arm linkage assembly isavailable to secure other components of the system, e.g. the pneumatichose used to draw slurry into the collection tank of the earthexcavator. In certain embodiments described herein, the linear actuatormay be attached at one end to one of the upper linkage arm and the lowerlinkage arm so that the linear actuator moves with movement thereof andat its other end directly to the tank body, though proximate themulti-arm linkage assembly's attachment to the tank, and have arelatively short stroke and allow for the placement of system componentsunder the multi-arm linkage assemblies. Thus, for example with respectto FIGS. 10A and 10B, a linear actuator 360 may be attached at a firstoperative end of the linear actuator (at 361) to one of the two linkagearms (e.g. upper linkage arm 302) at a second operative end of thelinear actuator (at 311) to the tank body proximate the second end ofthe linkage assembly (attached to the tank body at axis 113) so thatactuation of linear actuator 360 in a first direction moves the twolinkage arms 302 and 304 pivotally with respect to each other and sothat actuation of the actuator in a second direction moves the twolinkage arms in the opposite pivotal direction with respect to eachother.

In certain embodiments described herein, for example with respect toFIG. 5A, consider the attachment between one end of the linear actuatorand the tank body (at 169A), so that a first end of the linear actuatoris movable about a pivot point and first axis (the axis through pin 169Acoming out of the page, in the perspective of FIG. 5A) that isperpendicular to the generally cylindrical tank's center axis 129 (FIG.4 ), and the attachment between the second end of the linear actuator(at 168A) and one of the upper linkage arm and the lower linkage arm (inthe example of FIG. 5A, upper linkage arm 102A), so that the linearactuator's second end is movable (with respect to the linkage arm towhich it is attached, in this instance linkage arm 102A) about a pivotpoint and second axis (the axis through pin 168A coming out of the page,in the perspective of FIG. 5A) that is perpendicular to the tank centeraxis. When door 326 is in its closed position against the open tank end,the first axis is between the second axis and the tank open end. Theaxis (coming out of and into the page) at pin 169A is between theparallel axis through pin 168A and the tank's open end. It should benoted that the first axis is between the second axis and the open tankend, e.g., because, on a line (in the page of FIG. 5A) passing throughboth axes and the door opening, the first axis (at pin 169A) is betweenthe other axis (at pin 168A) and the open end, on that line. “Between,”however, does not require that the three features be so aligned. Thus,e.g., if the tank door opening is considered with respect to a verticalfirst plane 310 that includes door opening periphery 74 and that isperpendicular to the tank center line 129 (FIG. 4 ), and the first axis(at pin 169A) is considered with respect to a vertical second plane 312that includes the first axis and is perpendicular to the tankcenterline, and the second axis (at pin 168A) is considered with respectto a vertical third plane 314 that includes the second axis and that isperpendicular to the tank centerline, then the first axis is between thesecond axis and the tank open end because second plane 312 is betweenfirst plane 310 and third plane 314. One or more of the embodimentsdiscussed below may also illustrate such features.

FIGS. 9A and 9B illustrate, e.g., a discharge door latching system 80Afor use with a discharge door 226 of a collection tank 14 of an earthexcavator system, such as is shown at FIG. 1 . Similar to theembodiments of discharge door latching system 80 previously discussedwith regard to FIGS. 4 through 8 , discharge door latching system 80Aincludes two linkage assemblies 200, one on each side of collection tank14. Each linkage assembly 200 includes an upper linkage arm 202, a lowerlinkage arm 204, and a linear actuator, in this instance a hydrauliccylinder, 260 having a cylinder housing 262 attached to tank body 15(via the same mounting location by which the lower linkage arm isattached to the tank body) and an extendable piston rod 264 attached toupper linkage arm 202. In the embodiment of FIGS. 9A and 9B, thehydraulic cylinder's attachment to the lower linkage arm and the lowerlinkage arm's point of attachment to the tank body are joined at thepoint 210 where the lower linkage arm pivotally attaches to the tankbody about axis 113. Thus, cylinder housing 262 pivots about axis 113both with respect to the tank body and with respect to lower linkage arm204 as the multi-arm linkage assembly moves between its operativeextreme positions. The free end of piston rod 264 is connected to upperlinkage arm 202 at a pivotal (e.g. pinned) connection 261 that, whenconsidered along the length of upper linkage arm 202, is between thepoint (axis 136) at which the upper linkage arm pivotally attaches tothe lower linkage arm and the point (axis 132) at which the upperlinkage arm pivotally attaches to the door, resulting in reversal of thecylinder's operation directions from that of the embodiments of FIGS.4-8 .

In operation, assume that door 226 is disposed in its fully openposition as shown in FIG. 9A. As illustrated in the Figure, cylinder 260is in its fully extended position. To close the door, the hydrauliccontrol system that controls the cylinder is actuated to cause thecylinder to retract. Since the lower end of cylinder housing 262 isfixed to the tank body at 210, the pinned connection 261 betweencylinder rod 264 and upper linkage arm 202 allows upper linkage arm 202to pivot downward in the CW direction about axis 136 with respect tolower linkage arm 204 (in response to the actuator movement and thedoor's weight). Simultaneously, lower linkage arm 204 pivots in the CCWdirection around axis 113, with the result that axis 136 moves in theCCW direction about axis 113. Retraction of the cylinder to its fullyretracted position, as illustrated in FIG. 9B, draws axis 136 overcenter with respect to the plane defined by axes 113 and 132, asdescribed above, with the periphery of door 226 seated against periphery74 (FIG. 8 ) about the tank's open end. To open the door from thisposition, the cylinder's hydraulic controls are operated to cause it toextend. This pushes upper linkage arm 202 so that it moves in the CWdirection about axis 132 and in the CCW direction about its axis 136,and pulls the lower linkage arm (through the pinned connection at axis136) in the CW direction about axis 113 and the CCW direction about axis136. The resulting movement of axis 132 to the right (in the perspectiveof FIG. 9B) causes the door to open about the axis of hinges 128.

FIGS. 10A and 10B illustrate an embodiment of a discharge door latchingsystem 80B for use with a discharge door 326 of a collection tank 14 ofan earth excavator system, such as in FIG. 1 , that is similar to theembodiment discussed with respect to FIGS. 9A and 9B, except that thelower end of the hydraulic cylinder is attached to the tank body via apivotal connection to a bracket attached to the tank body that is notcoincident with axis 113, rather than via the pivotal connection of thelower linkage arm to the tank body. Similar to the embodiments ofdischarge door latching system 80 previously discussed with regard toFIGS. 4 through 8 , discharge door latching system 80B includes twolinkage assemblies 300, one on each side of tank 14. Each linkageassembly 300 includes an upper linkage arm 302, a lower linkage arm 304,and a linear actuator, in this instance a hydraulic cylinder, 360 havinga cylinder housing 362. Cylinder housing 362 is attached to the tankbody via a pivotal connection to a bracket 363 that is affixed to theside wall of tank body 15, rather than via the pivotal connection oflower linkage arm 304 to the tank body. The cylinder's extendable pistonrod 364 is pivotally attached to upper linkage arm 302 through a pivotpin connection at 361. While cylinder housing 362 is pivotally attachedto the tank body about an axis 311 (extending into and out of the pageof FIGS. 10A and 10B) of a pivot pin connection, the pivotal connectionbetween the cylinder housing and the tank at 311 remains proximate theposition at which one end of the linkage assembly (in this instance, thelower linkage arm) attaches to the tank body. In this embodiment and theembodiments of FIGS. 4-8 (see FIG. 5A) and 9A-9B (see FIG. 9A), thelinear actuator is attached at a first operative end to one of the upperand lower linkage arms and at its opposite second operative end to thetank body so that, when the door is closed over the tank body's openend, the axis about which the cylinder's second operative end moves withrespect to the tank body is between the axis about which the cylinder'sfirst operative end moves with respect to the one of the upper and lowerlinkage arm and the tank body open end. The operation of the embodimentillustrated in FIGS. 10A and 10B in moving the multi-arm linkage betweenits extreme positions is similar to the corresponding operation of theembodiment of FIGS. 9A and 9B.

FIGS. 11A and 11B illustrate an embodiment of a discharge door latchingsystem 80C for use with a discharge door 426 of a collection tank 14 ofan earth excavator system, such as in FIG. 1 , that is similar to theembodiment discussed with respect to FIGS. 9A and 9B, except that thelower end of the hydraulic cylinder is attached to the lower linkage armat a point on the lower linkage arm offset from the lower linkage arm'spivotal connection to the tank body, rather than directly at the pivotalconnection of the lower linkage arm to the tank body. Similar to theembodiments of discharge door latching system 80 previously discussedwith regard to FIGS. 4 through 8 , discharge door latching system 80Cincludes two linkage assemblies 400, one on each side of tank 14. Eachlinkage assembly 400 includes an upper linkage arm 402, a lower linkagearm 404, and a linear actuator, in this instance a hydraulic cylinder,460 having a cylinder housing 462 attached to lower linkage arm 404 andan extendable piston rod 464 attached to upper linkage arm 402. Cylinderhousing 462 is pivotally attached to lower linkage arm 404 at a pinnedconnection 463 that is offset (along the length of the lower linkagearm) from the pivotal connection between the lower linkage arm and thetank body at pivot pin connection 410. Thus, cylinder housing 462 pivotsabout pinned connection 463 (about an axis extending into and out of thepage of FIGS. 11A and 11B), and also about axis 113, as the multi-armedlinkage assembly moves between its extreme positions during itsoperation as disclosed herein.

Like the embodiments described with respect to FIGS. 4-8 , the linearactuator of the embodiment illustrated in FIGS. 11A and 11B are attacheddirectly to and between the lower linkage arm and the upper linkage arm.In this embodiment and the embodiments of FIGS. 4-8 and 9A-9B, thecylinder is attached at one operative end to the upper linkage arm andat its other operative end to the tank body via the lower linkage arm.In this embodiment and the embodiment of FIGS. 4-8, 9A-9B, and 10A-10B,the linear actuator is attached at a first operative end to one of theupper and lower linkage arms so that the first operative end moves withmovement of the one of the upper and lower linkage arms and at itsopposite second operative end to the tank body (in this instance, viathe lower linkage arm so that the second operative end moves with thelower linkage arm) so that, when the door is closed over the tank body'sopen end, the axis about which the cylinder's second operative end moveswith respect to the tank body is between the axis about which thecylinder's first operative end moves with respect to the one of theupper and lower linkage arm and the tank body open end.

The operation of the embodiment illustrated in FIGS. 11A and 11B issimilar to the operation of the embodiment illustrated in FIGS. 9A and9B, referenced above.

FIGS. 12A, 12B, and 12C illustrate a discharge door latching system 80Dfor use with a discharge door 526 of a collection tank 14 of an earthexcavator system 10, such as is also shown at FIG. 1 . Similarly to theembodiments of discharge door latching system 80 previously discussedwith regard to FIGS. 4 through 8 , discharge door latching system 80Dincludes a linkage assembly 500 on both sides of tank 14, each having anupper linkage arm 502, a lower linkage arm 504, and a linear actuator,in this instance a hydraulic cylinder, 560 having a cylinder housing 562mounted to lower linkage arm 504 and an extendable piston rod 564mounted to upper linkage arm 502. The connection points between upperlinkage arm 502, lower linkage arm 504, and actuating cylinder 560 oflinkage assembly 500 are the same as those of upper linkage arm 102,lower linkage arm 104, and actuating cylinder 160 of linkage assembly100 of the embodiments of FIGS. 4-8 (see, e.g., FIG. 5A). However,latching system 80D differs from latching system 80 in that rather thanattaching linkage assembly 500 adjacent an outer surface of tank body 15of tank 14, linkage assembly 500 is mounted inside of tank 14, withininternal chamber 111 (see, also, FIG. 8 ). In this embodiment, lowerlinkage arm 504 is attached to the tank body, not at an end of pivot bar110 as in the embodiments of FIGS. 4-8 , but rather at the center of thesupport tube 115 (see also FIG. 8 ). The through hole through lowerlinkage arm 504 may be fitted with a bearing assembly to facilitate thelower linkage arm's rotation about axis 113 that extends through thecenter of support tube 115, into and out of the page in the perspectiveof FIG. 12B.

The end of upper linkage arm 502 opposite the upper linkage arm's endthat attaches to lower linkage arm 504 at the pinned connection thatdefines axis 136 is configured to adjustably receive a threaded portionof an eye bolt 534. Eye bolt 534 has an eye (not shown) that ispivotally attached in a pinned connection (a pin may be connected to theinner panel, e.g., by tabs welded to the panel) to the interior surfaceof the domed panel portion of door 526 (e.g. at the center of the domedpanel) so that upper linkage arm 502 is pivotable with respect to door526 about axis 132, which extends into and out of the page of the viewof FIG. 12B.

Because, in this embodiment, the (a) vertical offset between (i) theconnection between the first end of the linear actuator and the upperlinkage arm at 168 and (ii) the connection between the two linkage armsat axis 136 and (b) the vertical offset between (iii) the connectionbetween the second end of the linear actuator and the lower linkage armat the axis through 169 and (iv) the connection between the lowerlinkage arm and the tank body at axis 113 aligns the hydraulic cylinderhorizontally when the door closes on the tank's open end, the linearactuator's (in this instance, the hydraulic cylinder's) direction ofoperation is aligned entirely with the door's bias force direction whenthe door is closed against the tank's open end, as in the embodiment ofFIGS. 4-8 . Because, in this embodiment, the connection between theupper and lower linkage arms at axis 136 is between (when consideredalong the length of the upper linkage arm) the connection between thepiston rod and the upper linkage arm at the axis of pinned connection168, the operation of the cylinder's extension and retraction in movingthe multi-arm linkage between its extremes of position is the same asthat of the embodiments of FIGS. 4-8 . In this embodiment, the cylinderis attached at one operative end to the upper linkage arm and at itsother operative end to the tank body via the lower linkage arm. Thelinear actuator is attached at a first operative end to one of the upperand lower linkage arms and at its opposite second operative end to thebody so that, when the door is closed over the tank body's open end, theaxis about which the cylinder's second operative end moves with respectto the tank body is between the axis about which the cylinder's firstoperative end moves with respect to the one of the upper and lowerlinkage arm and the tank body open end. It will be understood thathydraulic fluid lines may be directed through sealed openings in thetank body wall to reach the cylinder for its operation.

FIGS. 13A-13E illustrate a discharge door latching system 80E for usewith a discharge door 626 of a collection tank 14 of an earth excavatorsystem, such as is shown at FIG. 1 . Similar to the embodiments ofdischarge door latching system 80 previously discussed with regard toFIGS. 4 through 8 , discharge door latching system 80E includes twolinkage assemblies 600, one on each side of tank 14. Each linkageassembly 600 includes an upper linkage arm 602, a lower linkage arm 604,and a linear actuator, in this instance a hydraulic cylinder, 660 havinga cylinder housing 662 attached to tank body 15 via a pinned connectionat 611 (which may also be considered to define an axis 611 extendinginto and out of the page of the view of FIGS. 13A-13E and about whichcylinder housing 662 pivotally moves as the multi-arm linkage assemblymoves between its extreme positions) and an extendable piston rod 664attached to lower linkage arm 604 at a pinned connection 168. Upperlinkage arm 602 and lower linkage arm 604 are pivotally connected at apinned connection that defines an axis 136 about which the upper andlower linkage arms pivot with respect to each other as they move throughthe motion driven by the linear actuator.

First end 601 of upper linkage arm 602 is configured to adjustablyreceive a threaded portion of an eye bolt 134. Eye bolt 134 has an eye(not shown) that is pivotally connected to door 626, and morespecifically to a first end of a cross bar (see, e.g., FIG. 4 , at 148)that is rigidly secured to a domed panel of discharge door 126 so thatthe upper linkage arm is pivotable with respect to, and pivotallyattached to, door 626 about an axis 132 that passes through the eyes ofthe eye bolts 134 on both sides of the tank body. Axis 132 is generallyperpendicular to longitudinal axis 129 (FIG. 4 ) and is the axis aboutwhich door 626 (including the cross bar) pivots with respect to thefirst ends of the first and second upper linkage arms. Moreover, thethreaded connection between upper linkage arm first end 601 and thecorresponding end of the cross bar allows for adjustment of the spacebetween the upper linkage arm first end and the cross bar end in thedirection of the bias force vector applied by the door into the tank'sopen end periphery 74 (see also FIG. 8 ).

The free end of piston rod 664 is connected to lower linkage arm 604 ata pivotal (e.g. pinned) connection 168 that, when considered along thelength of lower linkage arm 604, is between the point (axis 113) atwhich the lower linkage arm pivotally attaches to the tank body and thepoint (axis 136) at which the lower linkage arm pivotally attaches tothe upper linkage arm. Like the embodiments of FIGS. 4-8 , the hydrauliccylinder of the embodiment illustrated in FIGS. 13A-13E retracts inmoving door 626 from its position closed over the open tank end to itsopened position disposed away from the open tank end and extends inmoving the door from the fully opened position to the fully closedposition.

The linear actuator is attached at a first operative end to one of theupper and lower linkage arms and at its opposite second operative end tothe body so that, when the door is closed over the tank body's open end,the axis about which the cylinder's second operative end moves withrespect to the tank body is between the axis about which the cylinder'sfirst operative end moves with respect to the one of the upper and lowerlinkage arm and the tank body open end.

In operation, assume that door 626 is disposed in its fully openposition as shown in FIG. 13E. As illustrated in the Figure, cylinder660 is in its fully retracted position. To close the door, the hydrauliccontrol system that controls the cylinder is actuated to cause thecylinder to extend. Since the lower end of cylinder housing 262 is fixedto the tank body at 611, this causes piston rod 664 to push lowerlinkage arm 604 in the CCW direction about axis 113, thereby causingupper linkage arm 602 to pivot in the CW direction about axis 136 withrespect to lower linkage arm 204, with the result that axis 136 moves inthe CCW direction about axis 113 and that door 626 pivots in the CWdirection about the axis (in and out of the page of these figures)defined by hinges 128. Extension of the cylinder to its fully extendedposition, as illustrated in FIG. 13A, draws axis 136 over center withrespect to a plane 675 (coming into and out of the page of FIG. 13A)defined by axes 113 and 132, as described above, with the periphery ofdoor 226 seated against periphery 74 (see also, FIG. 8 ) about thetank's open end. To open the door from this position, the cylinder'shydraulic controls are operated to cause it to retract. This pulls lowerlinkage arm 602 so that so that it moves in the CW direction about axis113 and pushes the upper linkage arm (through the pinned connection ataxis 136) in the CCW direction about axis 136. This causes the door toopen to the right (in the perspective of FIGS. 13A-13E) and the door tothereby pivot in the CCW direction about the axis of the door hinges128. The resulting movement of axis 132 to the right (in the perspectiveof FIGS. 13A-13E) causes the door to open about the axes of the hinges128 to the fully opened position, as shown at FIG. 13E.

It should be appreciated by those skilled in the art that variousmodifications and variations can be made in the present disclosurewithout departing from the scope and spirit of the disclosure. It isintended that the present disclosure cover such modifications andvariations as come within the scope and spirit of the appended claimsand their equivalents.

What is claimed is:
 1. A collection tank for a mobile vacuum excavator,the collection tank comprising: a generally cylindrical body having atank centerline; a front with a closed end; and a rear with an open endhaving a sealing flange that defines a first plane perpendicular to thetank centerline; a door pivotally connected to the generally cylindricalbody and having a periphery that abuts the sealing flange of the openend when the door is closed over the open end; a first linkage armhaving an end pivotally connected to the body; a second linkage armhaving a first end pivotally connected to the door and a second end,wherein when the door is closed over the open end, the first end of thesecond linkage arm is rearward of the first plane and the second end ofthe second linkage arm is forward of the first plane; and an actuatorhaving a first end that is pivotally connected to one of the firstlinkage arm or the second linkage arm at a first pivot point lying in athird plane that is perpendicular to the tank centerline; and a secondend having a second pivot point located between the first plane and thethird plane; wherein the first pivot point and the second pivot pointlie in a plane that is parallel to or generally parallel to the tankcenterline.
 2. The collection tank of claim 1, wherein the first linkagearm and the second linkage arm are pivotally attached to one anothersuch that a first pivotal movement of the first linkage arm and thesecond linkage arm with respect to each other drives the first end ofthe second linkage arm and the end of the first linkage arm relativelyaway from each other, and so that a second pivotal movement of the firstlinkage arm and the second linkage arm with respect to each other movesthe first end of the second linkage arm and the end of the first linkagearm relatively toward each other.
 3. The collection tank of claim 2,wherein the actuator is attached to the first linkage arm and to thesecond linkage arm so that the actuator moves with movement of the firstlinkage arm and with movement of the second linkage arm, and so thatactuation of the actuator in a first direction moves the first linkagearm and the second linkage arm in the first pivotal movement, and sothat actuation of the actuator in a second direction moves the firstlinkage arm and the second linkage arm in the second pivotal movement.4. The collection tank of claim 1, wherein the first linkage arm, thesecond linkage arm, and the actuator together define a linkage assemblythat is disposed on a first side of the collection tank, and furthercomprising a second linkage assembly attached to and between the doorand the body on a second side of the collection tank, opposite the firstside.
 5. The collection tank of claim 1, wherein the first linkage arm,the second linkage arm, and the actuator together define a linkageassembly that is disposed inside the body.
 6. The collection tank ofclaim 1, wherein the first linkage arm is pivotally attached to the bodyat a body mounting end about a mount axis, the second linkage arm ispivotally attached to the door at a door mounting end about a doorclosure axis, so that the door mounting end moves with movement of thedoor, and the second linkage arm is pivotally attached to the firstlinkage arm at a door latch axis, so that a first pivotal movement ofthe first linkage arm and the second linkage arm with respect to eachother drives the body mounting end of the first linkage arm and the doormounting end of the second linkage arm relatively away from each other,and so that a second pivotal movement of the first linkage arm and thesecond linkage arm with respect to each other drives the body mountingend of the first linkage arm and the door mounting end of the secondlinkage arm relatively toward each other, wherein a door latch plane isdefined by the mount axis and the door closure axis, and wherein thedoor latch axis is on one side of the door latch plane when the actuatoris in a retracted state, and the door latch axis is on an opposite sideof the door latch plane when the actuator is in an extended state. 7.The collection tank of claim 1, wherein each of the first linkage arm,the second linkage arm, and the actuator lie in a common plane.
 8. Thecollection tank of claim 1, wherein the second linkage arm is formedwith a yoke-shaped end configured to receive at least a portion of thefirst linkage arm therein.
 9. The collection tank of claim 8, whereineach of the first linkage arm and the actuator are pivotally attached tothe yoke-shaped end of the second linkage arm such that at least aportion of the first linkage arm and at least a portion of the actuatorare positioned between yoke-halves of the yoke-shaped end.
 10. Thecollection tank of claim 1, wherein the first linkage arm and the secondlinkage arm are disposed with respect to each other so that, when thedoor moves to a closed position with respect to the collection tank, apivotal attachment between the first linkage arm and the second linkagearm moves over center.
 11. The collection tank of claim 1, wherein thedoor has a dome-shaped panel and has an elongated cross bar rigidlyconnected to the dome-shaped panel, and wherein the second linkage armis attached to the door through the elongated cross bar.
 12. Thecollection tank of claim 1, wherein the first end of the actuator ispivotally connected to the second linkage arm.
 13. The collection tankof claim 1, wherein the first end of the actuator is pivotally connectedto the first linkage arm.
 14. The collection tank of claim 1, whereinthe actuator is a hydraulic cylinder.
 15. The collection tank of claim1, further comprising a hinge between the body and the door.
 16. Acollection tank for a mobile vacuum excavator, the collection tankcomprising: a generally cylindrical body having a front with a closedend, and a rear with an open end having a periphery; a door having aperiphery that abuts the periphery of the open end when the door isclosed over the open end; and a linkage assembly having a first endattached to the door so that the first end moves with movement of thedoor, and a second end attached to the body, wherein the linkageassembly comprises a first arm, a second arm pivotally attached to thefirst arm so that a first pivotal movement of the first arm and thesecond arm with respect to each other drives the first end and thesecond end relatively away from each other, and so that a second pivotalmovement of the first arm and the second arm with respect to each othermoves the first end and the second end relatively toward each other, andan actuator attached to the first arm and to the second arm so that theactuator moves with movement of the first arm and with movement of thesecond arm and so that actuation of the actuator in a first directionmoves the first arm and the second arm in the first pivotal movement,and so that actuation of the actuator in a second direction moves thefirst arm and the second arm in the second pivotal movement.
 17. Thecollection tank of claim 16, wherein the first arm is attached to thebody at the first end of the linkage assembly, and wherein the secondarm is attached to the door at the second end of the linkage assembly.18. The collection tank of claim 16, wherein the actuator is a hydrauliccylinder.
 19. The collection tank of claim 18, wherein the actuator isattached to the first arm and the second arm so that the first directioncorresponds to retraction of the hydraulic cylinder and so that thesecond direction corresponds to extension of the hydraulic cylinder. 20.The collection tank of claim 16, wherein the first arm and the secondarm are disposed with respect to each other so that, when the door movesto a closed position with respect to the collection tank, a pivotalattachment between the first arm and the second arm moves over center.21. The collection tank of claim 16, wherein the first arm is pivotallyattached to the body at a body mounting end about a mount axis, thesecond arm is pivotally attached to the door at a door mounting endabout a door closure axis, so that the door mounting end moves withmovement of the door, and the second arm is pivotally attached to thefirst arm at a door latch axis so that a first pivotal movement of thefirst arm and the second arm with respect to each other drives the bodymounting end of the first arm and the door mounting end of the secondarm relatively away from each other, and so that a second pivotalmovement of the first arm and the second arm with respect to each otherdrives the body mounting end of the first arm and the door mounting endof the second arm relatively toward each other, wherein a door latchplane is defined by the mount axis and the door closure axis, andwherein the door latch axis is on one side of the door latch plane whenthe actuator is in a retracted state and the door latch axis is on anopposite side of the door latch plane when the actuator is in anextended state.